102 research outputs found
Aridibacter nitratireducens sp. nov., a member of the family Blastocatellaceae, class Blastocatellia, isolated from an African soil
No full textMembers of the class Blastocatellia are frequently found in soils with a neutral and (slightly) basic pH where they constitute an important fraction of the microbial community. A novel representative of the class Blastocatellia was isolated from a Ghanaian soil and was characterized in detail. Cells of strain A24_SHP_-5_238T were non-motile rods that divided by binary fission and formed orange to salmon-coloured colonies on agar plates. Strain A24_SHP_-5_238T tolerated pH values of pH 6.0-9.0 (best growth at pH 7.0-8.5) and temperature values of 8-45 °C (best growth at 33-40 °C). It grew chemo-organoheterotrophically on several sugars, a few amino acids, organic acids and different complex protein substrates. In addition, strain A24_SHP_-5_238T was able to use nitrate as an alternative electron acceptor in the absence of oxygen. Major fatty acids of A24_SHP_-5_238T were iso-C15 : 0, summed feature 1 (C13 : 0 3-OH/iso-C15 : 1 H), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), anteiso-C17 : 0 and anteiso-C15 : 0. The major quinone was MK-8, and the DNA G+C content was 53.5 mol%. The closest described phylogenetic relatives were Aridibacter famidurans A22_HD_4HT and Aridibacter kavangonensis Ac_23_E3T with a 16S rRNA gene sequence identity of 97.6 and 97.2 %, respectively. The DNA-DNA hybridization values (<28.5 %) confirmed that A24_SHP_-5_238T represents a novel species within the genus Aridibacter. Based on its morphological, physiological and molecular characteristics, we propose the novel species Aridibacter nitratireducens sp. nov. (type strain A24_SHP_-5_238T = DSM 102177T = CECT 9235T)
VIDÉK, VALLÁS ÉS POLITIKA PROFESSOR MANDICA MANJA KOVAČEVIĆ RÁDIÓMŰSORAIBAN
No full textDoctor Mandica Manja Kovačević (1929–2011) was a professor at several Croatian teacher training colleges (Čakovec, Kutina, and Gospić) and the author of three books and some 60 papers in various journals. She moderated a weekly ten-minute program for the local radio station in Gospić in the first decade of the 21st century. Thus, more than 300 radio contributions were produced, of which seventy were published in the book “Life on the Highest Wave” (Gospić, 2010). By researching and presenting phonographic recordings not included in the aforementioned book, this paper focused on the topics dealing with the affairs from the Croatian society in the first decade of the 21 century serving as an original sample by means of which Professor Kovačević had presented her personal views and attitudes resulting from life experience and local and traditional expectations. Professor Kovečević’s original reviews have attracted the attention of a large number of listeners because they have been able to find answers to questions that are usually contemplated by a contemporary man torn apart between existential challenges and spiritual search.Mandica Manja Kovačević (1929–2011) több horvátországi tanárképző főiskola professzora volt (Čakovec, Kutina és Gospić), emellett három könyv szerzője, és mintegy 60 tanulmánya jelent meg különböző folyóiratokban. A 21. század első évtizedében moderátora volt egy hetente sugárzott műsornak a gospići helyi rádióban, amelynek következtében, több mint 300 műsort készített, s ezek egy részéből (70 műsor) könyvet jelentetett meg „Life on the Highest Wace” (Gospić, 2010) címmel. A tanulmány célja, hogy górcső alá vonja azokat a hangfelvételeket, amelyek a könyvben nem kerültek feldolgozásra, s kifejezetten azok a témák kerülnek elemzésre, amelyek az évezred elejének horvát társadalmával foglalkoznak. A hangfelvételek elemzése során kiindulópontnak tekintjük Mandica Manja Kovačević által közvetített nézeteket és attitűdöket, ugyanis a professzor asszony szemlélete széles körű figyelmet keltett, hiszen a hallgatók választ kaptak olyan kérdésekre, mint az egzisztenciális és spirituális kutatás szétválasztása
Two adhesive systems cooperatively regulate axon ensheathment and myelin growth in the CNS
No full textCentral nervous system myelin is a multilayered membrane produced by oligodendrocytes to increase neural processing speed and efficiency, but the molecular mechanisms underlying axonal selection and myelin wrapping are unknown. Here, using combined morphological and molecular analyses in mice and zebrafish, we show that adhesion molecules of the paranodal and the internodal segment work synergistically using overlapping functions to regulate axonal interaction and myelin wrapping. In the absence of these adhesive systems, axonal recognition by myelin is impaired with myelin growing on top of previously myelinated fibers, around neuronal cell bodies and above nodes of Ranvier. In addition, myelin wrapping is disturbed with the leading edge moving away from the axon and in between previously formed layers. These data show how two adhesive systems function together to guide axonal ensheathment and myelin wrapping, and provide a mechanistic understanding of how the spatial organization of myelin is achieved
From Light Microscopy to Analytical Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB)/SEM in Biology: Fixed Coordinates, Flat Embedding, Absolute References
No full textCorrelative light and electron microscopy (CLEM) has been in use for several years, however it has remained a costly method with difficult sample preparation. Here, we report a series of technical improvements developed for precise and cost-effective correlative light and scanning electron microscopy (SEM) and focused ion beam (FIB)/SEM microscopy of single cells, as well as large tissue sections. Customized coordinate systems for both slides and coverslips were established for thin and ultra-thin embedding of a wide range of biological specimens. Immobilization of biological samples was examined with a variety of adhesives. For histological sections, a filter system for flat embedding was developed. We validated ultra-thin embedding on laser marked slides for efficient, high-resolution CLEM. Target cells can be re-located within minutes in SEM without protracted searching and correlative investigations were reduced to a minimum of preparation steps, while still reaching highest resolution. The FIB/SEM milling procedure is facilitated and significantly accelerated as: (i) milling a ramp becomes needless, (ii) significant re-deposition of milled material does not occur;and (iii) charging effects are markedly reduced. By optimizing all technical parameters FIB/SEM stacks with 2 nm iso-voxels were achieved over thousands of sections, in a wide range of biological samples
REGION, RELIGION AND POLITICS PRESENTED ON RADIO BY PROFESSOR MANDICA MANJA KOVAČEVIĆ, PH.D.
No full textDoctor Mandica Manja Kovačević (1929–2011) was a professor at several Croatian teacher training colleges (Čakovec, Kutina, and Gospić) and the author of three books and some 60 papers in various journals. She moderated a weekly ten-minute program for the local radio station in Gospić in the first decade of the 21st century. Thus, more than 300 radio contributions were produced, of which seventy were published in the book “Life on the Highest Wave” (Gospić, 2010). By researching and presenting phonographic recordings not included in the aforementioned book, this paper focused on the topics dealing with the affairs from the Croatian society in the first decade of the 21 century serving as an original sample by means of which Professor Kovačević had presented her personal views and attitudes resulting from life experience and local and traditional expectations. Professor Kovečević’s original reviews have attracted the attention of a large number of listeners because they have been able to find answers to questions that are usually contemplated by a contemporary man torn apart between existential challenges and spiritual search.Mandica Manja Kovačević (1929–2011) több horvátországi tanárképző főiskola professzora volt (Čakovec, Kutina és Gospić), emellett három könyv szerzője, és mintegy 60 tanulmánya jelent meg különböző folyóiratokban. A 21. század első évtizedében moderátora volt egy hetente sugárzott műsornak a gospići helyi rádióban, amelynek következtében, több mint 300 műsort készített, s ezek egy részéből (70 műsor) könyvet jelentetett meg „Life on the Highest Wace” (Gospić, 2010) címmel. A tanulmány célja, hogy górcső alá vonja azokat a hangfelvételeket, amelyek a könyvben nem kerültek feldolgozásra, s kifejezetten azok a témák kerülnek elemzésre, amelyek az évezred elejének horvát társadalmával foglalkoznak. A hangfelvételek elemzése során kiindulópontnak tekintjük Mandica Manja Kovačević által közvetített nézeteket és attitűdöket, ugyanis a professzor asszony szemlélete széles körű figyelmet keltett, hiszen a hallgatók választ kaptak olyan kérdésekre, mint az egzisztenciális és spirituális kutatás szétválasztása
Metabolic engineering of light-driven cytochrome P450 dependent pathways into <i>Synechocystis</i> sp. PCC 6803
No full textSolar energy provides the energy input for the biosynthesis of primary and secondary metabolites in plants and other photosynthetic organisms. Some secondary metabolites are high value compounds, and typically their biosynthesis requires the involvement of cytochromes P450s. In this proof of concept work, we demonstrate that the cyanobacterium Synechocystis sp. PCC 6803 is an eminent heterologous host for expression of metabolically engineered cytochrome P450-dependent pathways exemplified by the dhurrin pathway from Sorghum bicolor comprising two membrane bound cytochromes P450s (CYP79A1 and CYP71E1) and a soluble glycosyltransferase (UGT85B1). We show that it is possible to express multiple genes incorporated into a bacterial-like operon by using a self-replicating expression vector in cyanobacteria. We demonstrate that eukaryotic P450s that typically reside in the endoplasmic reticulum membranes can be inserted in the prokaryotic membranes without affecting thylakoid membrane integrity. Photosystem I and ferredoxin replaces the native P450 oxidoreductase enzyme as an efficient electron donor for the P450s both in vitro and in vivo. The engineered strains produced up to 66 mg/L of p-hydroxyphenylacetaldoxime and 5 mg/L of dhurrin in lab-scale cultures after 3 days of cultivation and 3 mg/L of dhurrin in V-shaped photobioreactors under greenhouse conditions after 9 days cultivation. All the metabolites were found to be excreted to the growth media facilitating product isolation. (C) 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved
Validation of a Hypothesis: Colonization of Black Smokers by Hyperthermophilic Microorganisms
No full textNewly erupted black smokers (hydrothermal vent chimneys) are sterile during their formation, but house hyperthermophilic microorganisms in substantial amounts in later stages. No direct experimental data exist by which mechanisms hyperthermophiles colonize newly erupted black smokers, but a scenario was proposed recently how this might happen. Here we combine high temperature light microscopy with electron microscopy to show that two hyperthermophilic Archaea, namely Pyrococcus furiosus and Methanocaldococcus villosus are able to adhere onto authentic black smoker material (BSM). We especially are able to directly observe the adhesion process via video recordings taken at high temperatures. These data validate the hypothesis that hyperthermophiles are transferred by serendipitous water currents to the outside of newly formed black smokers and react within seconds to the there prevailing high temperatures by very fast movements. They scan the surface of the hydrothermal chimneys via a much slower zigzag seek-movement and adhere via their flagella at a suitable place, building up biofilms
Agents of Global Competition in the International Student Market
No full textThis chapter focuses on the agents of competition and cooperation in global higher education. More specifically, it tackles international student mobility and foregrounds the changing nature of competition between individuals, universities, and countries. It engages with Pavel Zgaga’s seminal work on the role of universities in society, the nature of knowledge, globalisation, and European higher education and its internationalisation efforts. In his work, Zgaga foregrounds three key processes. First, a struggle between competition and cooperation among regions, countries, and institutions. Second, a struggle over various competing aims and approaches to student mobility supporting a variety of cultural, political or economic rationales. Finally, a struggle and power play between various actors. Zgaga analysed these dichotomies at the macro and meso policy level. My analysis complements his work at the micro level by investigating how policy is materialised and enacted at the Association of International Educators (NAFSA) annual conference and expo. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
- …
